Atrial arrhythmia, such as Atrial Fibrillation (AF), is a common cardiac arrhythmia which may contribute to significant risks of electrophysiological disorders, leading to morbidity and mortality, as well as thrombo-embolism and stroke. Atrial arrhythmia, such as AF, is a common cardiac pathology in the older population, and is an irregularity of the heart rhythm. Instead of only one area in the atrium initiating an electrical signal, multiple different areas generate electrical signals. A complex of electrical impulses or wavelets spreads over atrial tissue and causes an atrial muscle to quiver or fibrillate, rather than contracting in an organized way. Some of the electrical impulses still travel down through the heart and make the bottom chambers squeeze or contract. The irregularity of the impulses traveling down from the atria makes the ventricles beat irregularly, so a pulse may feel irregular. Sometimes AF can make the pulse fast and irregular or slow and irregular. A heart in atrial fibrillation does not beat efficiently. It may not be able to pump enough blood into a body with each heartbeat. Due to the insufficient blood flow, the heart may drastically increase the heart rate. For example the heart rate in atrial fibrillation may range from 100 to 175 beats per minute. The normal range for a heart rate is 60 to 100 beats per minute.
AF alone is not a life-threatening arrhythmia, but it can be extremely bothersome and sometimes dangerous. For example, in atrial fibrillation, the chaotic rhythm may cause blood to pool in an atria and form clots. If a blood clot forms, it may dislodge and travel to the brain and block blood flow, causing a stroke. The risk of stroke in atrial fibrillation depends on age and blood pressure, diabetes, or a history of heart failure or previous stroke, and other factors. Atrial fibrillation can be paroxysmal (episodes come and go on their on), persistent (episodes come and last until rhythm is re-established) or permanent (the heart stays in AF despite efforts to convert to a normal rhythm). There may be many causes and factors which may induce atrial fibrillation, such as high blood pressure, atrial or valve abnormality, alcohol and family history. Early detection of atrial arrhythmia helps to reduce risk and discomfort and facilitates bringing a heart back to normal heart rhythm using an energy based cardioverter electrical shock, for example. Known waveform morphologies and time domain parameter analysis of atrial arrhythmia focus on P wave analysis which concerns the depolarization procedure of the atrium. P wave changes (atrial depolarization signals) alone may not be able to provide early detection of atrial pathologies.
Known analysis based on P wave morphology changes fails to differentiate atrial arrhythmia type and categorize severity of atrial arrhythmia. Further known methods for complex cardiac atrial arrhythmia identification and diagnosis using a surface ECG signal are subjective and need extensive expertise for accurate interpretation and appropriate cardiac rhythm management. This is particularly the case in the early stage of the atrial fibrillation in which the P wave morphology distortion and changes are small and atrial arrhythmias are not easy to detect. Known atrial arrhythmia (such as fibrillation) detection methods include heart rate variability detection. However the efficiency and reliability of known clinical approaches is often inadequate, especially in a noisy environment since atrial activities may be buried in noise. In known clinical applications, atrial arrhythmia diagnosis and treatment, especially in an early stage, are typically heavily dependent on physician experience. A system according to invention principles addresses these deficiencies and related problems.